Chicago is a “sanctuary city.” That sounds nice, kind of like Oscar Schindler protecting Jews from the Nazis. It actually means protecting illegal aliens who commit crimes from being punished and deported. When President Donald Trump took office, some 300 jurisdictions, including 106 cities, actively interfered with federal law enforcement.

The Chicago case arose from a drunk driver and illegal alien. Shortly after completing probation for a DUI offense, Saul Chavez ran over and killed Dennis McCann, a pedestrian headed to dinner with a friend. Surely Chavez deserved to pay for his crime.

Yet Cook County refused to notify Immigration and Customs Enforcement (ICE) when Chavez was released on bond. Naturally, he fled.

Noted Attorney General Jeff Sessions: “To a degree perhaps unsurpassed by any other jurisdiction, the political leadership of Chicago has chosen deliberately and intentionally to adopt a policy that obstructs this country’s lawful immigration system. They have demonstrated an open hostility to enforcing laws designed to protect law enforcement—Federal, state, and local—and reduce crime, and instead have adopted an official policy of protecting criminal aliens who prey on their own residents.”

Responded the mayor: “Chicago will not be blackmailed into changing our values, and we are and will remain a welcoming city.” However, the president didn’t say that Chicago couldn’t continue to protect criminals. Only that it had to do so on its own dime. If the city wants federal dollars, it should comply with federal law.

Obviously, many Americans disagree passionately over the issue of immigration. But not in question is the fact that immigration law is made by Congress and enforced by the president.

Many other issues, such as welfare, are best left to states to decide and manage. But not immigration. Ultimately the federal government must decide who is allowed to enter America and under what conditions.

What the Constitution does not do, however, is allow the federal government to force states to enforce national law. It is federalism 101. The Supreme Court ruled that the Tenth Amendment prevents Uncle Sam from “commandeering” the states for its own purposes.

The result is a good balance. States (which include cities and other localities) cannot override federal policy. They cannot enact statutes inconsistent with national law. That includes who enters America.

However, states retain sufficient sovereignty to refuse to cooperate if they so choose. In this case, some local governments contend that cooperating with ICE discourages those here illegally from cooperating with law enforcement.

At the same time, however, as the president recognizes, the Constitution does not require Washington to hand out money to states. Indeed, such transfers can be bad policy, since local politicians have less incentive to be careful with “free money” from Congress. And it is especially bad policy for the national government to underwrite states which seek to thwart national policy.

Hence the Trump administration’s proposal to withhold money from so-called “sanctuary cities.” They still can act as they wish. But they will lose federal funds.

There’s some $27 billion at stake for the 106 self-declared municipal sanctuaries for law-breaking. Actually, the administration’s announcement alone was sufficient to scare Miami straight. Florida’s largest city agreed to stop obstructing immigration law enforcement.

The more general reaction, however, was for recipients to run to court, tying up the administration’s proposal. New York and San Francisco are but two which say they are going to follow Chicago to the courthouse.

Of course, filing lawsuits now seems to be the “American way.” However, the Founders never intended for judges to rule the U.S. The people voted for political leaders who promised to clamp down on illegal immigration. As in the travel ban case, which is headed to the Supreme Court, where the president likely will be vindicated.

In the meantime, some states are acting to back federal law. In May Texas began implementing legislation which bars local officials from withholding immigration information from federal agencies. Bills have been introduced in at least 31 other states to bar cities and counties from becoming sanctuaries to illegal aliens and criminals.

For too long local officials have obstructed federal immigration law with impunity. The Constitution protects the right of states to say no. But the Constitution does not require national taxpayers to subsidize lawbreakers. The president’s message is simple: play ball or pay the price.

Ken Blackwell is a member of the Policy Board of the American Civil Rights Union and a Fellow at the Family Research Council. He was a Senior Domestic Policy Advisor to Trump Presidential Transition Team.